Thermal auto-change air diffuser

Abstract

An actuator for a diffuser in a fluid distribution system is disclosed in which the actuator includes a shape memory alloy wire. The shape memory alloy wire cooperates with at least one diffuser blade to automatically change the flow pattern from the diffuser based on the temperature of the fluid provided to the diffuser. Also disclosed is a diffuser and a fluid distribution system including this actuator.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to, and the benefit under 35 U.S.C. § 119(e) of, U.S. Provisional Application 60/649,712 filed Feb. 3, 2005, titled THERMAL AUTO-CHANGE AIR DIFFUSER, which application is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present application is directed to fluid distribution systems, such as heating, ventilation, and air conditioning (HVAC) systems, and, more particularly, to control of the flow of fluid, such as air, from the distribution systems.

BACKGROUND

HVAC systems provide air or another fluid to compartments, such as rooms, in a controlled manner to distribute the air in the room in a particular way. This provides comfort for the occupants of the room, for example, cooling in summer months and heating in winter months. Often, a diffuser is provided at the outlet from the system into the room to direct the flow of air entering the room. The diffuser has one or more blades that direct the flow of air.

When both heating and cooling are provided by a single diffuser, the buoyancy effects of air potentially create a problem. Heating air and cooling air are preferably provided to a room in different patterns. Cold air will naturally sink and hot air will naturally rise. Ceiling diffusers fight this problem by blowing cold air horizontally across a ceiling and hot air vertically down into the space. A sidewall diffuser mounted close to the floor will blow cold air vertically up along a wall toward the ceiling and warm air along the floor.

Some diffusers are designed to be manually adjustable to change between heating and cooling blow patterns. Some diffusers actively sense supply temperature and change geometry through the use of a powered control system. Others use passive means of actuation like bi-metallic strips or wax motors.

Changing between heating and cooling modes in an HVAC system with a ceiling diffuser can lead to discomfort of the room's occupants or other problems. For example, when heat is supplied to a ceiling diffuser set for cooling (horizontal blow) and the diffuser is not adjusted, the heated air will stay at the top of the conditioned space due to air buoyancy effects. The room may still feel cold due to stratification of the air. This adds to the cost of heating a room as the heating system must run longer to lower the stratified zone.

When cooling is supplied to a ceiling diffuser set for heating (vertical blow) and the diffuser is not adjusted, the cold air may blow directly onto an occupant of the space. If a diffuser is manually adjustable and installed in a ceiling, it may be inaccessible or difficult for most occupants to change. The adjustments may require going into the plenum space above the ceiling. Not all plenum spaces are accessible.

Actively adjusting diffusers with an outside energy source (electric, pneumatic) adds to the cost of conditioning the room. Passive methods of adjusting a diffuser are generally slow in actuating. This may result in a room being slowly “swept” with a curtain of air as the diffuser switches from heating to cooling.

SUMMARY

The present invention is directed to control of the distribution of a fluid, such as air or another gas or combination of gases, to a compartment, such as a room, automatically, based on sensing the temperature of the fluid in the fluid distribution system. This is done without requiring an outside energy source or action on the part of the room's occupants. As the temperature of the fluid in the distribution system reaches a predetermined value, the blades in the diffusers are automatically moved to provide the fluid in a particular direction.

A shape memory alloy wire cooperates with at least one blade of the diffuser to change position of the blade in response to the temperature of the fluid. In one embodiment, the shape memory alloy wire is connected directly or indirectly with the blade.

One exemplary embodiment of the present invention includes an actuator. The actuator has an engagement mechanism for engaging a blade of the diffuser, a bias apparatus connected to the engagement mechanism, and a shape memory alloy wire connected to the engagement mechanism. The shape memory alloy wire expands or contracts based on the temperature of the fluid in the distribution system, such that when the shape memory alloy wire contracts, the engagement mechanism is moved to a first position which moves the blade to a corresponding first position, and when the shape memory alloy wire expands, the engagement mechanism is moved to a second position which moves the blade to a corresponding second position.

For example, if the temperature of the fluid in the fluid distribution system increases past a first predetermined value, the shape memory wire contracts. When the shape memory wire contracts, it pulls on the engagement mechanism and moves it to a first position. If the engagement mechanism is engaging the diffuser blade, then the diffuser blade is moved to a corresponding first position.

When the temperature of the fluid in the distribution system decreases past a second predetermined value, the shape memory wire expands and the bias apparatus pulls on the engagement mechanism and moves it to a second position. If the engagement mechanism is engaging the diffuser blade, then the diffuser blade is moved to a corresponding second position.

When the diffuser blade is the second corresponding position, the fluid is directed into the compartment in a different direction than when the diffuser blade is in the first corresponding position. In one embodiment, the fluid is air and the compartment is a room.

Also disclosed is a diffuser for use in a fluid distribution system. The diffuser includes at least one blade for directing the flow of fluid from the distribution system, and an actuator as described above. Also disclosed is a fluid distribution system having one or more diffusers as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, which are incorporated in and constitute a part of this specification, embodiments of the invention are illustrated, which, together with a general description of the invention given above, and the detailed description given below, serve to exemplify the principles of this invention, wherein:

FIG. 1 is a side view illustrating an actuator exemplifying the present invention in use with a straight blade;

FIG. 2 is a top view of the actuator of FIG. 1;

FIG. 3 is a perspective view of actuator of FIG. 1;

FIG. 4 is a perspective view illustrating a straight-bladed diffuser exemplifying the present invention;

FIG. 5 is a cutaway side view of the diffuser of FIG. 4;

FIGS. 5A and 5B are detail views of the areas A and B, respectively, of FIG. 5;

FIG. 6 is an end view of the diffuser of FIG. 5 illustrating a horizontal blow configuration;

FIG. 7 is an end view of the diffuser of FIG. 5 illustrating a vertical blow configuration;

FIG. 8 is a side view illustrating an actuator exemplifying the present invention in use with a curved blade;

FIG. 9 is a top view of the actuator of FIG. 8;

FIG. 10 is a perspective view of actuator of FIG. 8;

FIG. 11 is an exploded perspective view of a blade assembly such as can be used with the actuator of FIG. 8;

FIG. 12 is a perspective view of the blade assembly of FIG. 11;

FIG. 12A is a detail view of Area A of FIG. 12;

FIG. 13 is an end view of the assembly of FIG. 12;

FIG. 14 is a perspective view illustrating a curved-bladed diffuser exemplifying the present invention;

FIG. 15 is a cutaway side view of the diffuser of FIG. 14;

FIG. 16 is an end view of the diffuser of FIG. 15 illustrating a horizontal blow configuration;

FIG. 17 is an end view of the diffuser of FIG. 15 illustrating a vertical blow configuration;

FIG. 18 is a perspective view illustrating a curved-bladed diffuser in an aluminum extrusion frame exemplifying the present invention;

FIG. 19 illustrates an elevation view of a typical blow pattern in an occupied space for a ceiling diffuser exemplifying the present invention;

FIG. 20 illustrates an elevation view of a typical blow pattern in an occupied space for a wall diffuser exemplifying the present invention; and

FIG. 21 illustrates a cutaway side view of an exemplary diffuser in accordance with the present invention having a shape memory alloy wire connected directly to a blade.

DETAILED DESCRIPTION

The present invention is directed to components of a fluid distribution system and to a fluid distribution system. The invention will be described in terms of the exemplary embodiments presented herein, but is limited only by the claims. For example, the following discussion describes the invention in terms of an air distribution system into a room, but the dispersion and distribution of any fluid, and not just air, into any compartment, or an open area, may be accomplished by the present invention. The fluid may be, for example, a gas of combination of gases other than air.

One diffuser in accordance with the present invention switches between a horizontal air pattern, for example, to a vertical air pattern, for example, dependent on the temperature of the air without any need for manual adjustment or outside energy source. The temperature of the air is measured or sensed, for example, at the inlet supply to the diffuser. Such a diffuser may be used in any HVAC application where a change of air pattern (change of diffuser geometry) is required with a corresponding change of temperature. This can encompass residential and commercial applications. It can be used not only with linear slot diffusers, but with other kinds of ceiling diffusers as well. It is also applicable to side wall diffuser applications.

The diffuser includes at least one diffuser blade and an actuator that engages at least one diffuser blade. The diffuser blade directs the flow of air into the room. The actuator includes an engagement mechanism to engage the diffuser blade. The engagement mechanism has, for example, a cam or tongs that engage different types of diffuser blades. The actuator also includes a bias apparatus that is part of or attached or connected, directly or indirectly, to the engagement mechanism. The bias apparatus includes, for example, a spring that is directly or indirectly attached to the engagement mechanism. The bias apparatus may also be, for example, integral with one or more elements of the actuator, such as by weight distribution of the engagement mechanism. The bias apparatus also includes providing an external weight cooperating with the engagement mechanism to return the engagement mechanism to a predetermined position. The integral or cooperating weight responds to gravity. The bias apparatus is any structure that tends to return the engagement mechanism to a predetermined position when no other forces are acting to change the position of the engagement mechanism.

The actuator further includes a wire that is at least partially composed of a shape memory alloy (SMA). A shape memory alloy is generally known as a metal that exhibits an almost rubber-like flexibility and an ability to be severely deformed and then returned to its original shape by temperature change.

The wire must have sufficient SMA to react to temperature changes in the air in the air distribution system and produce the actuator changes described herein. References herein to SMA wire include wire partially composed of a SMA and wire that is completely composed of SMA. In one embodiment, the SMA wire is attached or connected, directly or indirectly, to the engagement mechanism. The SMA wire cooperates, directly or indirectly, with at least one diffuser blade to effect a change in the position of the blade when the temperature of the fluid reaches one or more preselected values.

Two exemplary actuator designs in which the SMA wire are used include a straight-blade application and a curved-blade application. The straight blade and the curved blade refer to the shape of blades within the diffuser used to direct and control the pattern of air distribution to the room. The straight-blade application actuator has “tongs” that engage and rotate, for example, a straight blade (FIGS. 1-3). The curved-blade application actuator has a cam that pushes on and rotates a different shape of blade (FIGS. 8-10). Other designs and applications may be employed without departing from the spirit and scope if the invention.

FIG. 1 illustrates an exemplary actuator 10 in accordance with the present invention. The actuator 10 includes an engagement mechanism (tongs) 12 to engage a straight blade assembly 14 (FIG. 4). This exemplary actuator 10 also includes a bracket 16 and a lever 18 connected to the bracket at pivot 20. The bracket 16 has a lever stop 22 that selectively prevents the lever 18 from pivoting.

An SMA wire 24 is connected to the engagement mechanism 12 and the lever 18. A spring 26 is connected to the engagement mechanism 12 and the lever 18.

FIGS. 2 and 3 illustrate a top view and a perspective view, respectively, of the exemplary actuator of FIG. 1.

In one embodiment, the engagement mechanism (tongs) 12 is used in the actuator 10 for a straight bladed diffuser 28, as illustrated in FIGS. 4-7. The blade 30 of the blade assembly 14 is punched in such way as to leave a tab 32 for the engagement mechanism 12 to engage. The blade pivots in bushings 34 in the ends of the plenum 36. The pivot is provided by nail point pins 38.

The plenum 36 of the diffuser 28 is made from formed sheet metal and the actuator 10 mounts to the side of the plenum 36 opposite the inlet. In the illustrated diffuser 28, the actuator 10 is mounted with rivets 40. The mounting hardware may be selected as desired and appropriate for the specific application without departing from the spirit and scope of the invention.

The actuator 10 is positioned in the inlet air stream in order to realize the full effect of the supply air temperature. There may be multiple blades 30 in any given diffuser 28, and the blades 30 may be of any desired length. The blade 30 may be punched at different locations depending on the length of the diffuser 28. Multiple actuators 10 may be needed in a single diffuser 28 depending on the number of blades 30. Likewise, a single actuator may be directly or indirectly connected to more than one blade to change position of more than one blade simultaneously.

FIGS. 8-10 illustrate another embodiment in which the actuator 110 is used with curved blades. The actuator 110 includes an engagement mechanism (cam) 112 to engage a curved blade assembly 114 (FIG. 14). This exemplary actuator 110 also includes a bracket 116 and a lever 118 connected to the bracket at pivot 120. The bracket 116 has a lever stop 122 that selectively prevents the lever 118 from pivoting.

An SMA wire 124 is connected to the engagement mechanism 112 and the lever 118. A spring 126 is connected to the engagement mechanism 112 and the lever 118.

FIGS. 9 and 10 illustrate a top view and a perspective view, respectively, of the exemplary actuator of FIG. 8.

The engagement mechanism (cam) 112 is used with a curved blade assembly 114, as illustrated in FIGS. 11-13. The blade assembly 114 includes a support bar 144 to which two blades 130 are clipped with clip 146. The blades 130 can swivel in the clip 146. On the bottom side of the support bar 144, at least one spreader spring 148 is fastened. The spreader spring 148 keeps the blades 130 spread out. The cam engagement mechanism 112 mounts to the top of the support bar 144 and has a tab 132 that holds one of the blades 130 in the “down” position. As the engagement mechanism 112 actuates, it moves the other blade 130 down while the spreader spring 148 returns it to the “up” position.

In one embodiment, the engagement mechanism (cam) 112 is used in the actuator 110 for a curved bladed diffuser 28, as illustrated in FIGS. 14-17. The blade assembly 114 is fastened by screws 134 in the ends of the plenum 136.

The plenum 136 of the diffuser 128 is made from formed sheet metal and the actuator 110 mounts to the side of the plenum 136 opposite the inlet. The mounting hardware may be selected as desired and appropriate for the specific application without departing from the spirit and scope of the invention.

The actuator 110 is positioned in the inlet air stream in order to realize the full effect of the supply air temperature. There may be multiple blades 130 in any given diffuser 128, and the blades 130 may be of any desired length. Multiple actuators 110 may be needed in a single diffuser 128 depending on the number of blade assemblies 114. Likewise, a single actuator may be directly or indirectly connected to more than one blade to change position of more than one blade simultaneously.

Another diffuser type is constructed with an aluminum extrusion frame 150 with a sheet metal plenum 136, as illustrated in FIG. 18. The blade assembly 114 is mounted to the aluminum frame spacers. The plenum 136 fits over the frame 150 and is fastened to the sides. This diffuser type may be used with the curved-blade diffuser or the straight-blade diffuser.

When the SMA wire is exposed to cold air, it expands and the return spring pulls the cam or tong mechanism. This moves the diffuser blade to a first position, such as to create horizontal blow of air. See FIGS. 6 and 16. When the SMA wire is exposed to hot air, it contracts and pulls the cam or tong mechanism in the opposite direction of the return spring. This moves a diffuser blade to a second position, such as to create vertical blow of air. See FIGS. 7 and 17. In other embodiments the expansion of the SMA wire leads to vertical blow and contraction of the SMA wire leads to horizontal blow. In yet other embodiments, the expansion/contraction of the SMA wire leads to other changes in direction of the disposition of the blade and corresponding direction of the flow or air, for example, right/left directing of the blow.

Exemplary resulting air distribution patterns are illustrated in FIGS. 19 and 20. FIG. 19 illustrates exemplary air flow patterns for a diffuser 200 in accordance with the present invention mounted in a ceiling. FIG. 20 illustrates exemplary air flow patterns for a diffuser 200 in accordance with the present invention mounted in a wall.

FIG. 21 illustrates an exemplary embodiment of a diffuser 200 in which an SMA wire 202 is connected directly to a blade 204. The SMA wire 202 may be connected directly to a plenum 206 or to a bracket 208 or anchored in any other way to effect a change in the position of the blade upon change of temperature of the air or other fluid. Any biasing apparatus, such as weight distribution of the blade 204 to respond to gravity, may be used to change the position of the blade 204 when the SMA wire 202 expands.

The actuator in accordance with the present invention uses the SMA wire to achieve the diffuser blade movement actuation. In one embodiment, the wire contracts in heating mode and expands in cooling mode. An outside energy source is not required.

The SMA wire has an internal hysteresis that is a material property of the alloy used. For example, the normal operating supply air temperatures for an HVAC system are 55° F. in cooling and 85° F. in heating. When an SMA alloy is at a temperature less than a first selected temperature, for example, 60° F., it is at its fully expanded state. As the air temperature increases, there is slight contraction of the material, but at a second selected temperature, for example, 80° F., there is a drastic contraction of the material and at any temperature above 80° F. the material will be fully contracted. Usually, the SMA wire will change its geometry within about 2 seconds, and preferably within about 1 second. The actual time for the SMA wire to undergo change depends on the material selected for the SMA wire (see below). Now as the same wire is cooled, it does not re-expand at 80° F. It only fully expands at 60° F.

This hysteresis results in the diffuser changing geometry only when the supply air has reached a critical temperature and it will make the change very fast. The SMA wire essentially undergoes a prompt or non-gradual change at selected temperatures. This enables the position of the blades in the diffuser to change rapidly. The actual time for the blades to change position will depend on the configuration of the diffuser and the direct or indirect connection between the SMA wire and the blade. This stops drafts on occupants in the room and avoids gradual sweeping of a curtain of air across room occupants.

In one embodiment, the material selected for the SMA wire is nitinol. Other SMA alloys may be used and may be selected to provide different temperature actuation ranges, based on availability, or for any other reason without departing from the spirit and scope of the invention. Other SMA alloys include copper/zinc/aluminum, copper/aluminum/nickel, silver/cadmium, gold/cadmium, copper/tin, copper/zinc, indium/titanium, nickel/aluminum, iron/platinum, manganese/copper, iron/manganese/silicon, and other nickel/titanium alloys. SMA alloys are sold, for example, under the brand names Muscle Wires®, Flexinol®, and BioMetal®, which are registered trademarks of Mondo-tronics, Inc., Dynalloy, Inc., and Toki Corporation, respectively.

While the present invention has been illustrated by the above description of embodiments, and while the embodiments have been described in some detail, it is not the intention of the applicants to restrict or in any way limit the scope of the invention to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicants' general or inventive concept.

Claims

1. An actuator for use in a fluid distribution system for the distribution of fluid in at least one selected pattern, the actuator comprising:

a. an engagement mechanism to engage at least one blade of the fluid distribution system to position or reposition the blade; and

b. a shape memory alloy wire connected to the engagement mechanism and capable of causing the engagement mechanism to change position,

wherein the shape memory alloy wire is capable of expanding or contracting based on the temperature of the fluid in the distribution system, such that when the shape memory alloy wire contracts, the engagement mechanism is moved to a first position and when the shape memory alloy wire expands, the engagement mechanism is moved to a second position.

2. The actuator of claim 1, further comprising a bias apparatus in cooperation with the engagement mechanism to cause the engagement mechanism to return to the second position when the shape memory wire expands.

3. The actuator of claim 2, wherein the bias apparatus comprises a spring in cooperation with the engagement mechanism.

4. The actuator of claim 1, wherein the blade of the fluid distribution system is a straight blade.

5. The actuator of claim 1, wherein the blade of the fluid distribution system is a curved blade.

6. The actuator of claim 1, wherein the shape memory alloy wire expands when the temperature of the fluid in the distribution system decreases below a first selected temperature.

7. The actuator of claim 1, wherein the shape memory alloy wire contracts when the temperature of the fluid in the distribution system increases above a second selected temperature.

8. The actuator of claim 1, wherein the shape memory alloy wire comprises nitinol, copper/zinc/aluminum, copper/aluminum/nickel, silver/cadmium, gold/cadmium, copper/tin, copper/zinc, indium/titanium, nickel/aluminum, iron/platinum, manganese/copper, iron/manganese/silicon, or other nickel/titanium alloys.

9. The actuator of claim 8, wherein the shape memory alloy wire comprises nitinol.

10. The actuator of claim 1, further comprising means for causing the engagement mechanism to move when the shape memory alloy wire expands.

11. A diffuser for use in a fluid distribution system for the distribution of fluid in. at least one selected pattern, comprising:

a. at least one blade for directing the flow of fluid; and

b. at least one shape memory alloy wire in direct or indirect cooperation with the blade and capable of causing the blade to change position in response to a temperature change in the fluid.

12. The diffuser of claim 11, further comprising at least one actuator, the actuator comprising an engagement mechanism for engaging the blade to position or reposition the blade; wherein the shape memory alloy wire is connected to the engagement mechanism and is capable of causing the engagement mechanism to change position.

13. The diffuser of claim 12, wherein the shape memory alloy wire is capable of expanding or contracting based on the temperature of the fluid in the distribution system, such that when the shape memory alloy wire contracts, the engagement mechanism is moved to a first position which moves the blade to a corresponding first position, and when the shape memory alloy wire expands, the engagement mechanism is moved to a second position which moves the blade to a corresponding second position.

14. The diffuser of claim 13, further comprising a bias apparatus in cooperation with the engagement mechanism to cause the engagement mechanism to return to the second position when the shape memory wire expands.

15. The diffuser of claim 14, wherein the bias apparatus comprises a spring in cooperation with the engagement mechanism.

16. The diffuser of claim 11, wherein the shape memory alloy wire is connected directly to the blade.

17. A fluid distribution system for distributing fluid into a space, comprising a diffuser comprising at least one blade and at least one actuator, the actuator comprising:

a. an engagement mechanism for engaging the blade to position or reposition the blade; and

b. a shape memory alloy wire connected to the engagement mechanism and capable of causing the engagement mechanism to change position.

18. The system of claim 17, wherein the shape memory alloy wire is capable of expanding or contracting based on the temperature of the fluid in the distribution system, such that when the shape memory alloy wire contracts, the engagement mechanism is moved to a first position which moves the blade to a corresponding first position, and when the shape memory alloy wire expands, the engagement mechanism is moved to a second position which moves the blade to a corresponding second position.

19. An actuator for use in a fluid distribution system for the distribution of fluid, the actuator comprising:

a. an engagement mechanism to engage at least one blade of the fluid distribution system to position or reposition the blade; and

b. means for automatically changing the position of the blade based on the temperature of the fluid without manual adjustment of the position of the blade and without an outside power source providing power to sense temperature of the fluid or to change the position of the blade.

20. The actuator of claim 19, wherein the means for automatically changing the position of the blade comprises means to cause a non-gradual change in the position of the blade.

21. The actuator of claim 19, wherein the means for automatically changing the position of the blade comprises a shape memory alloy wire connected to the blade or to the engagement mechanism and capable of causing the blade to change position.

22. A method of automatically switching a diffuser between vertical fluid flow pattern and horizontal fluid flow pattern, comprising:

a. having blade position of the diffuser biased to one of the vertical fluid flow pattern or the horizontal fluid flow pattern;

b. sensing the temperature of the fluid with a shape memory alloy wire;

c. actuating a change of blade position to the opposite of the bias position by the shape memory alloy wire in response to the temperature of the fluid.

23. The method of claim 22, further comprising actuating a change of blade position back to the bias position in response to the temperature of the fluid.

24. The method of claim 22, wherein actuating a change of blade position comprises changing the blade position non-gradually.